We perform a comprehensive global QCD analysis of spin-dependent parton distribution functions (PDFs), combining all available data on inclusive and semi-inclusive deep-inelastic scattering (DIS), as well as inclusive weak boson and jet production in polarized <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions, simultaneously extracting spin-averaged PDFs and fragmentation functions. Including recent Jefferson Lab DIS data at high <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>, together with subleading power corrections to the leading-twist framework, allows us to verify the stability of the PDFs for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mn>2</mn></msup><mo>≥</mo><mn>4</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mn>2</mn></mrow></msup></math> and quantify the uncertainties on the spin structure functions more reliably. We explore the use of new lattice QCD data on gluonic pseudo-Ioffe time distributions, which, together with jet production and high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> DIS data, improve the constraints on the polarized gluon PDF. The expanded kinematic reach afforded by the data into the high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> region allows us to refine the bounds on higher-twist contributions to the spin structure functions, and test the validity of the Bjorken sum rule.

United States

C. Cocuzza

Australia

N.T. Hunt-Smith

W. Melnitchouk

N. Sato

A.W. Thomas

Global QCD analysis of spin PDFs in the proton with high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> and lattice constraints

The relativistic quark model is used to study the processes of heavy tetraquark <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>c</mi><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo></math> production in the Higgs boson decay. We consider quark-gluon, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mi>Z</mi></math>-boson, and quark-gluon loop decay mechanisms with the production of a fully charmed tetraquark. Relativistic interaction amplitudes are constructed and decay widths are calculated taking into account relativistic corrections in the decay amplitude connected with the relative motion of quarks and antiquarks.

Russia

F.A. Martynenko

A.V. Eskin

A.P. Martynenko

Production of heavy tetraquarks in rare exclusive decays of the Higgs boson

ATLAS, a general-purpose experiment at the Large Hadron Collider (LHC), makes use of a large internationally-distributed computing infrastructure, including over $$10^6$$ TB of managed data on disk and tape and almost one million simultaneously running CPU cores. Upgrades for the High-Luminosity LHC (HL-LHC) will increase the required computing resources by a factor of 3–4 by the beginning of the 2030s, and by an order of magnitude before the conclusion of data taking at the beginning of the 2040s. These resources are spread over around 100 computing sites worldwide. Efforts are underway within the experiment to evaluate and mitigate various aspects of the environmental impact of the sites, with the additional long-term goal of making recommendations to the sites that will significantly reduce the total expected environmental impact in the HL-LHC era. These efforts take several forms: building awareness in the experiment community, adjusting aspects of the computing policy, and modifications of data center configurations, either in ways that take advantage of particular features of ATLAS workloads or in generic ways that reduce the environmental impact of the computing resources. This paper describes the ongoing investigations and approaches that have already provided useful and actionable outcomes.

France

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

Italy

United Kingdom

B. Acharya

A. Ackermann

C. Bourdarios

Poland

L. Adamczyk

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

Spain

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

S. Ahuja

China

X. Ai

G. Aielli

A. Aikot

M. Tamlihat

B. Aitbenchikh

M. Akbiyik

Sweden

T. Åkesson

A. Akimov

Japan

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G. Albouy

S. Alderweireldt

Z. Alegria

M. Aleksa

I. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

Saudi Arabia

H. Ali

S. Ali

S. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B. Allbrooke

J. Allen

P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z. Alsolami

A. Fernandez

M. Cardoso

M. Alviggi

M. Aly

Brazil

Y. Coutinho

A. Ambler

C. Amelung

M. Amerl

C. Ames

T. Amezza

D. Amidei

B. Amini

K. Amirie

A. Amirkhanov

Portugal

S. Santos

K. Amos

D. Amperiadou

S. An

C. Anastopoulos

T. Andeen

J. Anders

A. Anderson

A. Andreazza

S. Angelidakis

A. Angerami

A. Anisenkov

A. Annovi

C. Antel

E. Antipov

M. Antonelli

F. Anulli

M. Aoki

The environmental impact, carbon emissions and sustainability of computing in the ATLAS experiment

In this work, we propose a new approach within modified $\textit{f}$($\textit{R}$, $\textit{G}$) gravity to explore a possible explanation for the accelerated expansion of the universe. Given the tensions in cosmological parameters, we investigate this class of theories, which unifies geometric corrections from both the Ricci scalar $\textit{R}$ and the Gauss–Bonnet term $\textit{G}$. By studying the $$f(R,G) = \alpha R^n {G}^m$$ model in conjunction with the Barrow holographic dark energy (BHDE) model, we provide a generalized framework to address dark energy (DE) through both curvature-based modifications and quantum-gravitational microstructure effects, thereby avoiding the need for a cosmological constant. Additionally, we estimate parameters using the most recent observational data, such as direct measurements of the Hubble parameter, BAO, and Type Ia supernova. Our findings demonstrate that the model offers a theoretical framework for explaining the accelerated expansion of the cosmos and late-time cosmic evolution. The evolution of the effective equation of state parameter, the deceleration parameter (DP), and the cosmographic parameters are thoroughly examined based on the best fit values of the model parameters. The classical stability of the BHDE model has also been addressed. The model provides a different way to study DE in modified gravity theories, despite the extra complexity it introduces.

India

Vipin Dubey

Study of barrow holographic dark energy in the framework of Gauss–Bonnet cosmology

This work presents a detailed analysis of the gravitational collapse of a shear-free radiating, spherically symmetric imperfect fluid. The interior spacetime, characterized by dissipative and anisotropic pressure processes, is matched to an exterior Vaidya spacetime. We choose forms of the gravitational potentials which generalize earlier well known models yielding new dynamical effects. The matter variables are well behaved and a horizon does not form for the linear form of the temporal behaviour of the potential. The role of gravitational complexity is studied. We find that complexity plays a central role in the collapse process and influences the evolution of anisotropy, inhomogeneous processes and dissipative effects. Notably we find that profiles of the matter variables are similar to complexity early in the evolution of the star but their magnitudes grow appreciably as the collapse proceeds.

Lindani Majozi

Megandhren Govender

Sunil Maharaj

Wesley Govender

Complexity driven by anisotropy, inhomogeneity and dissipation

Naveed Iqbal

Pakistan

S. Khan

Mohammad Alshammari

Wael Mohammed

M. Ilyas

Erratum: Non-static, torsion-inspired hyperbolically symmetric stars with anisotropy and dissipation

Symmetric teleparallel gravity (STG) can be regarded as a modified gravity theory that lacks diffeomorphism symmetries, which complicates the calculation of its degrees of freedom. In this study, we analyze the linear perturbations of general STG models on a Minkowski background, considering both scenarios with and without scalar couplings. Furthermore, we provide lower bounds for the number of degrees of freedom associated with each model.

Dehao Zhao

Linear perturbations of symmetric teleparallel gravity on Minkowski background

A measurement of event-shape variables is presented, using a data sample produced in a special run with approximately one inelastic proton-proton collision per bunch crossing. The data were collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>64</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">μ</mi><msup><mrow><mi mathvariant="normal">b</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math>. A number of observables related to the overall distribution of charged particles in the collisions are corrected for detector effects and compared with simulations. Inclusive event-shape distributions, as well as differential distributions of event shapes as functions of charged-particle multiplicity, are studied. None of the models investigated are able to satisfactorily describe the data. Moreover, there are significant features common amongst all generator setups studied, particularly showing data being more isotropic than any of the simulations. Multidimensional unfolded distributions are provided, along with their correlations.

Armenia

V. Chekhovsky

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

H. Kwon

T. Van Laer

P. Van Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

Y. Hong

S. Lowette

I. Makarenko

Measurement of event shapes in minimum-bias events from proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>